You may need to file a nonresident return for the income earned - depending on the income earned and the filing requirements. Yes, mileage is a reasonable method.
You will claim the full income in your resident state. If you file a nonresident return, prepare it first so you can claim a credit on your resident return.
You get credit for the lower state tax on the lowest taxable amount.
- Each state calculates taxable income differently.
- Each state has its own tax rate/ system.
- You get the lowest of both categories as a tax credit.